Hello all, I'm just new to this whole chicken thing. We've recently gotten about fourty chickens. Layer, don't know what they're breed are, and a few banties. They were bought in three lots at a farm auction, the first bunch we were assured were very healthy one year hens, then came the banties, and last about 25 older hens. Everything was going ok up until about ten days ago. We've lost seven chickens, and it looks like they're four more on the brink. What they're exhibiting: dirty looking, lethargic, nasal secretions, sneezing, a couple of the sick hens have bulging eyes where it looks like they're loosing feathers around them, they're stools are a runny, brown colour -- no blood that I can see and finally they just give up. Egg laying has decreased. I've started them on erythomycin antibiotic in their water, but am wondering if I am treating them properly, and if there is anything else I can do? Also, not all the flock are exhibiting symtoms, but if this is something that can spread I want to nip it in the bud. Tomorrow is barn cleaning day (that's where they're housed) and any suggestions you may have would be greatly appreciated. Thanks.